app.py

import gradio as gr
import numpy as np
import numpy_financial as npf
import pandas as pd
import matplotlib.pyplot as plt

def amortization_report(principal, rate_percent, periods):
    """
    Generate and return an amortization schedule with plots.
    """
    rate = rate_percent / 100  # Convert from percent to decimal
    payment = -npf.pmt(rate, periods, principal)
    interest = -npf.ipmt(rate, range(1, periods + 1), periods, principal)
    principal_paid = -npf.ppmt(rate, range(1, periods + 1), periods, principal)
    balance = principal - principal_paid.cumsum()

    df = pd.DataFrame({
        'Year': range(1, periods + 1),
        'Payment': [round(payment, 2)] * periods,
        'Interest': interest.round(2),
        'Principal': principal_paid.round(2),
        'Balance': balance.round(2)
    })

    # Plot
    fig, axs = plt.subplots(1, 2, figsize=(12, 5))

    axs[0].plot(df['Year'], df['Interest'], label='Interest', color='red', marker='o')
    axs[0].plot(df['Year'], df['Principal'], label='Principal', color='green', marker='o')
    axs[0].set_title('Payment Breakdown')
    axs[0].set_xlabel('Year')
    axs[0].set_ylabel('Amount')
    axs[0].grid(True)
    axs[0].legend()

    axs[1].plot(df['Year'], df['Balance'], label='Remaining Balance', color='blue', marker='o')
    axs[1].set_title('Remaining Balance Over Time')
    axs[1].set_xlabel('Year')
    axs[1].set_ylabel('Balance')
    axs[1].grid(True)
    axs[1].legend()

    plt.tight_layout()
    return df, fig

demo = gr.Interface(
    fn=amortization_report,
    inputs=[
        gr.Number(label="Loan Amount (Principal)", value=100000),
        gr.Number(label="Annual Interest Rate (%)", value=5.00, precision=2),
        gr.Number(label="Number of Periods (Years)", value=10)
    ],
    outputs=[
        gr.Dataframe(label="Amortization Schedule"),
        gr.Plot(label="Payment Charts")
    ],
    title="📊 Amortization Report",
    description="Enter your loan details to view the amortization schedule and payment breakdown over time."
)

if __name__ == "__main__":
    demo.launch()